JP2012007134A - Adhesive resin composition, cover lay, adhesive film, metal-clad laminate and flexible printed circuit board - Google Patents

Abstract

To provide an adhesive resin composition, a cover lay, an adhesive film, a metal-clad laminate, and a flexible printed wiring board that are excellent in solder heat resistance and high-temperature sliding bending properties after moisture absorption.
A curing agent includes (A) an epoxy resin, (B) a curing agent, and (C) a thermoplastic resin, and the epoxy resin contains 1 to 50% by mass of a urethane-modified epoxy resin. Is blended at a ratio of 30 to 175 parts by mass with respect to 100 parts by mass of the epoxy resin, the thermoplastic resin is a polyvinyl acetal resin, and the thermoplastic resin is 50 to 300 parts by mass with respect to 100 parts by mass of the epoxy resin. An adhesive resin composition characterized by being blended in proportions.
[Selection figure] None

Description

  The present invention relates to an adhesive resin composition, a coverlay, an adhesive film, a metal-clad laminate, and a flexible printed wiring board.

  A flexible printed circuit (FPC) is excellent in flexibility, and it is often used as a circuit board in the head part of a hard disk drive or a circuit board built in a mobile phone by taking advantage of its excellent bending performance. ing.

  A flexible printed wiring board can be generally obtained by thermocompression bonding a metal-clad laminate and a coverlay. Here, the metal-clad laminate is formed by providing a metal layer made of copper or the like on a base film made of polyimide or the like, and the coverlay is formed by providing an adhesive layer on an insulating film made of polyimide or the like. Is. In the metal-clad laminate, an adhesive layer may be interposed between the metal foil and the base film.

  Examples of the adhesive resin composition used for the adhesive layer include an adhesive composition comprising an epoxy resin, a crosslinked acrylonitrile-butadiene rubber modified with a carboxylic acid, a curing agent, a curing accelerator, and an inorganic filler. It is known (see Patent Document 1 below).

JP 2006-169446 A (Example 4)

  By the way, in general, an adhesive composition for a flexible printed wiring board is required to have excellent solder heat resistance after moisture absorption. When the flexible printed wiring board is used by being attached to a movable part such as an arm of a magnetic head used in a hard disk device, in addition to the above characteristics, it is required to have excellent sliding and bending characteristics at high temperatures. .

  However, although the adhesive composition described in Patent Document 1 described above is excellent in solder heat resistance after moisture absorption, the sliding and bending characteristics at high temperatures (for example, 80 ° C.) may be insufficient.

  The present invention has been made in view of the above circumstances, and is an adhesive resin composition, a cover lay, an adhesive film, a metal-clad laminate, and a flexible printed wiring that are excellent in solder heat resistance and high-temperature sliding bending characteristics after moisture absorption. The purpose is to provide a board.

  As a result of intensive studies to solve the above problems, the present inventor found that the carboxylic acid-modified cross-linked acrylonitrile-butadiene rubber blended as a soft component in the adhesive composition described in Patent Document 1 was subjected to high-temperature sliding bending. It was found that this was a factor that deteriorated the characteristics. As a result of further earnest research, the inventor used a specific thermoplastic resin different from the carboxylic acid-modified crosslinked acrylonitrile-butadiene rubber as a flexible component, and a predetermined percentage of urethane-modified epoxy resin. It has been found that the above problems can be solved by blending the epoxy resin and setting the blending amount of the curing agent and the thermoplastic resin with respect to the epoxy resin within a predetermined range, thereby completing the present invention.

  That is, the present invention includes (A) an epoxy resin, (B) a curing agent, and (C) a thermoplastic resin, and the epoxy resin contains 1 to 50% by mass of a urethane-modified epoxy resin. The curing agent is blended at a ratio of 30 to 175 parts by mass with respect to 100 parts by mass of the epoxy resin, the thermoplastic resin is a polyvinyl acetal resin, and the thermoplastic resin is based on 100 parts by mass of the epoxy resin. It is the adhesive resin composition characterized by being mix | blended in the ratio of 50-300 mass parts.

  This adhesive resin composition is excellent in solder heat resistance after moisture absorption and high-temperature sliding bending characteristics.

  Moreover, this invention is equipped with the insulating film and the adhesive bond layer provided on the said insulating film, The said adhesive bond layer is formed using said adhesive resin composition, It is characterized by the above-mentioned. It is a coverlay.

  According to this coverlay, the adhesive layer is formed using an adhesive resin composition that is excellent in solder heat resistance after moisture absorption. For this reason, when mounting an electronic component or the like on a flexible printed wiring board manufactured by bonding the coverlay of the present invention to a metal-clad laminate, the swelling of the adhesive layer can be suppressed, The peeling of the adhesive layer can be sufficiently suppressed. Moreover, since the adhesive resin composition is also excellent in high-temperature sliding bending characteristics, the bending life of the flexible printed wiring board at high temperatures can be extended.

  Moreover, this invention is an adhesive film containing the adhesive bond layer formed using the said adhesive resin composition.

  This adhesive film is excellent in solder heat resistance and high-temperature sliding bending characteristics after moisture absorption.

  The present invention further includes a base film, a metal layer provided on one surface side of the base film, and an adhesive layer provided between the base film and the metal layer, wherein the adhesive layer is as described above. It is a metal-clad laminate characterized by being formed using an adhesive resin composition.

  According to this metal-clad laminate, the adhesive layer is formed using an adhesive resin composition that is excellent in solder heat resistance after moisture absorption. For this reason, when mounting an electronic component or the like on a flexible printed wiring board manufactured by bonding the metal-clad laminate of the present invention to a cover lay, the swelling of the adhesive layer can be suppressed, The peeling of the adhesive layer can be sufficiently suppressed. In addition, since the adhesive resin composition is also excellent in high temperature sliding bending characteristics, it can extend the bending life at high temperature of a flexible printed wiring board manufactured by bonding the metal-clad laminate of the present invention to a coverlay. .

  Furthermore, the present invention provides the above-described cover lay and a metal-clad laminate having a metal layer provided on one surface side of the base film, the adhesive layer of the cover lay, and the metal layer of the metal-clad laminate. It is a flexible printed wiring board characterized by thermocompression-bonding in the state which faced.

  According to this flexible printed wiring board, the adhesive layer is formed using the adhesive resin composition having excellent solder heat resistance after moisture absorption. For this reason, when mounting an electronic component etc. on the flexible printed wiring board of the present invention with solder, the swelling of the adhesive layer is suppressed, or the peeling of the adhesive layer from the insulating film or the base film is sufficiently suppressed. be able to. Moreover, since the adhesive resin composition is also excellent in high-temperature sliding bending characteristics, the flexible printed wiring board of the present invention can extend the bending life at high temperatures.

  According to the present invention, an adhesive resin composition, a coverlay, an adhesive film, a metal-clad laminate, and a flexible printed wiring board that are excellent in solder heat resistance and high-temperature sliding bending characteristics after moisture absorption are provided.

It is sectional drawing which shows one Embodiment of the flexible printed wiring board which concerns on this invention. It is sectional drawing which shows components required for manufacture of the flexible printed wiring board of FIG. It is a top view which shows the copper circuit pattern formed in the single-sided board used for evaluation of a high temperature sliding bending characteristic in an Example and a comparative example. It is a figure which shows the state which is performing the high temperature sliding bending test with respect to the printed wiring board which concerns on an Example and a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail. In all the drawings, the same or equivalent components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a cross-sectional view showing a preferred embodiment of a flexible printed wiring board according to the present invention. As shown in FIG. 1, the flexible printed wiring board 100 includes a base film 1. An adhesive layer 2 is provided on the surface 1 a of the base film 1, a metal layer 3 for forming a circuit is provided on the adhesive layer 2, and an adhesive layer is provided on the adhesive layer 2 so as to cover the metal layer 3. 4 is provided, and an insulating film 5 is provided on the adhesive layer 4.

  On the other hand, a reinforcing plate 7 is provided on the back surface 1 b of the base film 1 via an adhesive layer 6. The reinforcing plate 7 is made of stainless steel, polyimide, or the like.

  Next, a method for manufacturing the flexible printed wiring board 100 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing components necessary for manufacturing the flexible printed wiring board of FIG.

  First, as shown in FIG. 2, a cover lay 10, a metal-clad laminate 20, a reinforcing plate 7, and an adhesive sheet 30 for bonding the metal-clad laminate 20 and the reinforcing plate 7 are prepared.

  The coverlay 10 is formed by providing an adhesive layer 14 on the insulating film 5 and can be obtained by applying an adhesive solution containing an adhesive resin composition on the insulating film 5 and drying it. Here, the adhesive layer 14 is formed using the adhesive composition, and is partially cured, for example, semi-cured. As the insulating film 5, for example, a film made of polyimide resin, polyethylene terephthalate resin, aramid resin or the like and having a thickness of about 3 μm to 50 μm can be used.

  The metal-clad laminate 20 is obtained by sequentially providing an adhesive layer 22 and a metal layer 3 on the base film 1, and applying an adhesive solution containing an adhesive resin composition on the base film 1 and drying it. It can be obtained by sticking the metal layer 3 on the adhesive layer 22 formed by the above. Here, the adhesive layer 22 is formed using an adhesive composition, and is partially cured, for example, semi-cured. As the base film 1, a resin film having electrical insulation and flexibility is used, and examples thereof include films made of resins such as polyimide, polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, and polyethersulfone. The metal layer 3 is made of copper foil or the like.

  The adhesive sheet 30 is also formed by applying an adhesive solution containing an adhesive resin composition onto a base film 1 on a substrate made of a polyethylene terephthalate film or the like that has been subjected to a mold release treatment, and then drying the adhesive solution. Obtainable.

  Then, the adhesive sheet 30, the metal-clad laminate 20, and the coverlay 10 are sequentially disposed on the reinforcing plate 7. At this time, the base film 1 of the metal-clad laminate 20 and the adhesive sheet 30 are made to face each other, and the adhesive layer 14 of the coverlay 10, the adhesive layer 22 and the metal layer 3 of the metal-clad laminate 20 are It is in a state of facing each other.

  Then, the reinforcing plate 7, the adhesive sheet 30, the metal-clad laminate 20 and the coverlay 10 are thermocompression bonded. As a result, the adhesive layer 14 of the cover lay 10 is cured to become the adhesive layer 4, the adhesive layer 22 of the metal-clad laminate 20 is cured to become the adhesive layer 2, and the adhesive sheet 30 is cured to become the adhesive layer 6. Become. Thus, the flexible printed wiring board 100 is obtained.

  Here, the adhesive resin composition used for the adhesive layer 14 of the coverlay 10, the adhesive layer 22 of the metal-clad laminate 20, and the adhesive sheet 30 includes (A) an epoxy resin and (B) a curing agent. And (C) a thermoplastic resin. The epoxy resin contains 1 to 50% by mass of a urethane-modified epoxy resin, and the curing agent is blended at a rate of 30 to 175 parts by mass with respect to 100 parts by mass of the epoxy resin. Moreover, a thermoplastic resin is comprised by the polyvinyl acetal resin, and the thermoplastic resin is mix | blended in the ratio of 50-300 mass parts with respect to 100 mass parts of epoxy resins.

  This adhesive resin composition is excellent in solder heat resistance after moisture absorption. For this reason, the flexible printed wiring board 100 can sufficiently suppress the occurrence of swelling and peeling even when heated to melt the solder when mounting an electronic component or the like. Moreover, since the adhesive resin composition is also excellent in high-temperature sliding bending properties, the bending life of the flexible printed wiring board 100 at high temperatures can be extended. Therefore, the flexible printed wiring board 100 is extremely useful as a flexible printed wiring board for movable parts such as an arm of a magnetic head used in a hard disk device that is exposed to a high temperature by operation.

  Next, the adhesive resin composition will be described in more detail.

(A) Epoxy resin The epoxy resin contains 1 to 50% by mass of a urethane-modified epoxy resin. Here, the urethane-modified epoxy resin is formed by introducing a urethane bond into an epoxy resin, and as the urethane-modified epoxy resin, for example, a urethane cross-linked epoxy resin can be used. The urethane-crosslinked epoxy resin can be obtained, for example, by reacting two or more hydroxyl groups of an epoxy resin having a hydroxyl group with a urethane polymer having an isocyanate group at the terminal. The urethane cross-linked epoxy resin thus obtained has a structure in which two or more epoxy resin molecules are cross-linked with a urethane polymer.

  When the content of the urethane-modified epoxy resin in the epoxy resin is less than 1% by mass, the adhesion between the urethane-modified epoxy resin and the metal layer 3 cannot be sufficiently increased, and the solder heat resistance after moisture absorption is significantly reduced. . On the other hand, when the content of the urethane-modified epoxy resin in the epoxy resin exceeds 50% by mass, the high-temperature sliding bending characteristics are deteriorated. The content of the urethane-modified epoxy resin in the epoxy resin is preferably 3 to 25% by mass because it is superior in solder heat resistance after moisture absorption and high-temperature sliding bending characteristics.

  The epoxy resin contains a urethane-modified epoxy resin and an epoxy resin that is not urethane-modified. Examples of such epoxy resins not modified with urethane include bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, alicyclic epoxy resins, glycidyl ester type epoxy resins, Glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, acrylic acid modified epoxy resin (epoxy acrylate), phosphorus-containing epoxy resin, and their halides (brominated epoxy resin, etc.) and hydrogenated products Can be mentioned. These epoxy resins may be used independently and may use 2 or more types together. Brominated epoxy resins and the like are particularly effective when flame resistance is required for the adhesive. Moreover, since an acrylic acid modified epoxy resin (epoxy acrylate) has photosensitivity, it is effective for imparting photocurability to the epoxy resin composition. These epoxy resins can also be used together with a novolak type phenol resin, a vinyl phenol resin, a brominated vinyl phenol resin, or the like that undergoes a crosslinking reaction.

(B) Curing agent As the curing agent, any curing agent that can be used for curing an epoxy resin can be used without particular limitation. For example, an aliphatic amine curing agent, an alicyclic amine curing agent. Secondary or tertiary amine curing agent, aromatic amine curing agent, acid anhydride curing agent, dicyandiamide, boron trifluoride amine complex salt, imidazole compound, phenol novolac resin having triazine structure, melamine resin, etc. Is mentioned. These may be used alone or in combination of two or more.

  A hardening | curing agent is mix | blended in the ratio of 30-175 mass parts with respect to 100 mass parts of epoxy resins. When the blending amount of the curing agent is out of the above range, the solder heat resistance after moisture absorption is lowered.

  Since the compounding quantity of a hardening | curing agent improves the solder heat resistance after moisture absorption more with respect to 100 mass parts of epoxy resins, it is preferable that it is 50-150 mass parts.

(C) Thermoplastic resin The thermoplastic resin imparts flexibility to the epoxy resin, and a polyvinyl acetal resin is used as the thermoplastic resin. The polyvinyl acetal resin is not particularly limited as long as it is a polymer having a vinyl acetal group in the molecule, but as shown in the following chemical formula (1), (a) a vinyl acetal unit, (b) a vinyl alcohol unit, and (c) A resin composed of vinyl acetate units is preferred because it improves adhesion and heat resistance.

  The thermoplastic resin is blended at a ratio of 50 to 300 parts by mass with respect to 100 parts by mass of the epoxy resin. When the blending amount of the thermoplastic resin is less than 50 parts by mass, the high temperature sliding bending property is deteriorated. On the other hand, when the blending amount of the thermoplastic resin exceeds 300 parts by mass, solder heat resistance after moisture absorption is lowered. The blending amount of the thermoplastic resin is preferably 100 to 250 parts by mass with respect to 100 parts by mass of the epoxy resin, since both the solder heat resistance after moisture absorption and the high temperature sliding bending characteristic are improved at the same time.

  Moreover, the adhesive resin composition of this invention may contain an additive etc. as needed. Examples of the additive include silica, mica, clay, talc, titanium oxide, calcium carbonate, a silane coupling agent, and imidazole.

  The present invention is not limited to the above embodiment. For example, in the said embodiment, although the flexible printed wiring board 100 is manufactured using the reinforcement board 7 and the adhesive agent sheet 30, these are not necessarily required and can be abbreviate | omitted. The adhesive layer 22 used for the metal-clad laminate 20 can also be omitted.

  Moreover, in the said manufacturing method, although the reinforcement board 7, the adhesive sheet 30, the metal-clad laminated board 20, and the coverlay 10 are piled up and the adhesive bond layers 14 and 22 and the adhesive sheet 30 are hardened collectively, flexible In order to obtain the printed circuit board 100, the adhesive layers 14 and 22 and the adhesive sheet 30 are not necessarily cured at once. For example, the reinforcing plate 7, the adhesive sheet 30, and the metal-clad laminate 20 are overlaid, the adhesive layer 22 and the adhesive sheet 30 are cured to obtain a laminated body, and then the laminated body and the coverlay 10 are overlaid. In addition, the flexible printed wiring board 100 can be obtained even if the adhesive layer 14 is cured.

  Hereinafter, although the content of the present invention will be described more specifically with reference to examples and comparative examples, the present invention is not limited to the following examples.

(Examples 1-13 and Comparative Examples 1-7)
An adhesive resin composition was prepared as follows.

  That is, the epoxy resin A, the urethane-modified epoxy resin, the curing agent, the thermoplastic resin A, and the thermoplastic resin B are dissolved and dispersed in an organic solvent with the formulation shown in Tables 1 to 3, and solid content (epoxy resin A, urethane-modified) An adhesive solution having a concentration of 20% epoxy resin, curing agent, thermoplastic resin A and thermoplastic resin B) was prepared. As for the organic solvent, in each example and comparative example, at least one selected from methyl ethyl ketone, xylene, and cyclohexanone 1-methoxy-2-propanol was appropriately selected and used.

In Tables 1 to 3, unless otherwise specified, the numerical unit represents part by mass. As the epoxy resin A, urethane-modified epoxy resin, curing agent, thermoplastic resin A, and thermoplastic resin B, the following were specifically used.
(1) Epoxy resin A:
Phenol aralkyl type epoxy resin (Nippon Kayaku NC3000)
(2) Urethane modified epoxy resin:
ADEKA EPU-78-13S (urethane cross-linked bisphenol type epoxy resin) manufactured by ADEKA
(3) Curing agent:
Phenolic resin (PSM-4326 manufactured by Gunei Chemical Co., Ltd.)
(4) Thermoplastic resin A:
Polyvinyl butyral resin (Denka Butyral # 6000-CS manufactured by Denki Kagaku Kogyo Co., Ltd.)
(5) Thermoplastic resin B:
Acrylic nitrile butadiene rubber (NBR, Nipol 1072 manufactured by Zeon Corporation)

[Evaluation]
(Solder heat resistance after moisture absorption)
The adhesive solution prepared above was applied to a polyimide resin film having a thickness of 25 μm (trade name: Kapton 100H, manufactured by Toray Du Pont Co., Ltd.) so that the thickness after drying was 10 μm, and this adhesive solution was dried. Thus, an adhesive layer was formed.

  Next, a rolled copper foil having a thickness of 18 μm was adhered to the adhesive surface of the adhesive layer formed on the polyimide resin film to obtain a single-sided plate.

  Subsequently, an adhesive solution is applied to another polyimide resin film having a thickness of 25 μm (trade name: Kapton 100H, manufactured by Toray DuPont Co., Ltd.) so that the thickness after drying becomes 20 μm, and dried to form an adhesive layer. A coverlay formed was obtained.

Next, the adhesive layer of the coverlay was bonded to the copper foil of the above single-sided plate and pressed at 170 ° C. and a pressure of 40 kg / cm ^{2 for} 40 minutes to produce a printed wiring board.

  This printed wiring board was cut into a 25 mm × 25 mm square, and a sample for evaluating solder heat resistance after moisture absorption was produced.

  The sample for evaluation was left in a wet heat oven maintained at 40 ° C. and 90% RH (relative humidity) for 4 days, and immediately after taking out from the oven, it was floated in a solder bath at 260 ° C. for 1 minute. The results are shown in Tables 1-3. In Tables 1 to 3, the case where the adhesive layer did not expand or peel in one minute is indicated as “◎”, and the case where the adhesive layer expands or peels off in 10 seconds or more and less than 60 seconds is indicated as “ “O” was displayed, and “x” was shown when the adhesive layer expanded or peeled off in less than 10 seconds. Note that “◎” was evaluated as having extremely high solder heat resistance after moisture absorption, and “◯” was evaluated as having high solder heat resistance after moisture absorption, and these were regarded as acceptable. On the other hand, “x” was evaluated as low solder heat resistance after moisture absorption, and was rejected.

(High temperature sliding bending characteristics)
An adhesive layer is formed by applying the adhesive solution prepared above to a polyimide resin film having a thickness of 25 μm (trade name: Kapton 100H, manufactured by Toray DuPont Co., Ltd.) so that the thickness after drying becomes 10 μm. A single-sided plate was obtained by bonding a rolled copper foil having a thickness of 18 μm to the surface of the adhesive layer.

  Next, a copper circuit pattern as shown in FIG. 3 was formed on the copper foil of this single-sided plate. Terminals were provided at the ends of the copper circuit. The unit of the dimension shown in FIG. 3 is mm.

  Next, an adhesive solution is applied to another polyimide resin film having a thickness of 25 μm (trade name: Kapton 100H, manufactured by Toray DuPont Co., Ltd.) so that the thickness after drying is 20 μm, and is dried. A formed coverlay was obtained.

Next, the cover layer adhesive layer is bonded to the copper foil surface of the single-sided plate on which the copper circuit pattern is formed, and pressed at 170 ° C. and a pressure of 40 kg / cm ^{2 for} 40 minutes to obtain high-temperature sliding bending characteristics. A printed wiring board 31 used for evaluation was produced.

Next, as shown in FIG. 4, the printed wiring board 31 was attached to the fixed jig 32 and the movable jig 33 arranged in parallel so that the bending radius r was 2 mm. Furthermore, the electric wire 34 was attached to each terminal of the printed wiring board, and the initial resistance value R ₀ between each terminal was measured in an 80 ° C. atmosphere by a resistance measuring device. Next, the resistance between each terminal is measured while reciprocating the movable jig 33 in a direction parallel to the fixed jig 32 in an atmosphere of 80 ° C. with a stroke amount of 20 mm and a reciprocating movement of 1000 times / min. The number of times the resistance increase rate was 10% or more was defined as the number of high temperature sliding bends. Here, the rate of increase in resistance is represented by the following formula when the resistance when bent a predetermined number of times is R and the initial resistance is R ₀ :
Resistance increase rate [%] = 100 × (R−R ₀ ) / R ₀
It is represented by In addition, if the number of high-temperature sliding bends was 50 million times or more, it was evaluated that it was excellent in high-temperature sliding bend characteristics, and the test was accepted. If the number of high-temperature sliding bends was less than 50 million, it was evaluated as being inferior to the high-temperature sliding bend properties and was rejected.

  From the results shown in Tables 1 to 3, it was found that the adhesive resin compositions of Examples 1 to 13 reached the acceptance criteria for the solder heat resistance after moisture absorption, and the number of high-temperature sliding bends was extremely large. On the other hand, it was found that the adhesive resin compositions of Comparative Examples 1 to 7 did not reach the acceptance criteria in any of the solder heat resistance after moisture absorption and the number of high temperature sliding bends.

  From the above, it was confirmed that the adhesive resin composition of the present invention was excellent in solder heat resistance after moisture absorption and high-temperature sliding bending characteristics.

DESCRIPTION OF SYMBOLS 1 ... Base film 2 ... Adhesive layer 3 ... Metal layer 4 ... Adhesive layer 5 ... Insulating film 6 ... Adhesive layer 7 ... Reinforcement board 10 ... Coverlay 14 ... Adhesive layer 20 ... Metal-clad laminate 22 ... Adhesive layer 30 ... Adhesive sheet 100 ... Flexible printed circuit board

Claims (5)

(A) an epoxy resin;
(B) a curing agent;
(C) a thermoplastic resin,
The epoxy resin contains 1 to 50% by mass of a urethane-modified epoxy resin,
The curing agent is blended at a ratio of 30 to 175 parts by mass with respect to 100 parts by mass of the epoxy resin,
The thermoplastic resin is a polyvinyl acetal resin;
The thermoplastic resin is blended at a ratio of 50 to 300 parts by mass with respect to 100 parts by mass of the epoxy resin,
An adhesive resin composition characterized by the above. An insulating film;
An adhesive layer provided on the insulating film,
The adhesive layer is formed using the adhesive resin composition according to claim 1,
Coverlay characterized by.   The adhesive film containing the adhesive bond layer formed using the adhesive resin composition of Claim 1. A base film,
A metal layer provided on one side of the base film;
An adhesive layer provided between the base film and the metal layer;
The adhesive layer is formed using the adhesive resin composition according to claim 1,
A metal-clad laminate. A metal-clad laminate having a metal layer on one surface side of the base film, and the coverlay according to claim 2, wherein the adhesive layer of the coverlay and the metal layer of the metal-clad laminate are opposed to each other. Thermocompression bonding in a state where
A flexible printed wiring board characterized by

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